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This Chapter of Enzymes Covers:

  • Structure and Functions of Enzymes
  • Co-factor, Prosthetic group, Apoenzyme and Holoenzyme
  • Characteristics of Enzymes
  • Factors affecting the Rate of Enzymes Action
  • Enzmyme inhibitors ( Reversible and Non-reversible )

ENZYMES(BIO-CATALYSTS)

Compounds are bio-impetus which accelerate the substance responses by bringing down “Vitality of initiation”.

ENERGY OF ACTIVATION

Measure of energy which is required to begin a synthetic response. On the other hand Energy required to break a (specific covalent) bond exhibit in reactant.

NOMENCLATURE OF ENZYMES

enzyme  is a Greek word implies En(in) and Zyme(yeast).

DISCOVERY OF ENZYME

Term “Enzyme” was authored by F.W Kuhne in 1978.

NATURE OF ENZYME

All enzymes are protein in nature with the exception of few which are nitrogenous acids like RNA-DNA(Ribozymes). Ribozymes catalyze responses in hereditary informations.

CHARACTERISTICS OF ENZYMES

Protein in nature and are framed by living cells.

May be intracellular or additional cell.

Stays unaltered amid and after the response.

Accelerate the rate of response by diminishing vitality of activity.

Particular in their tendency.

Warm touchy and follow up on specific (ideal) temp.

Each has particular substrate pH for its action.

Activity can be modify by activators and inhibitors.

CLASSIFICATION OF ENZYME (ON THE BASIS OF STRUCTURE)

Unadulterated or Simple Enzyme comprise of just protein (e.g.Amylase and Pepsin) Conjugated or Holoenzymes: May contain a non-protein part “Prosthetic gathering” also (e.g. Phosphatase and Peptidase)

Holoenzyme = Apoenzyme + Prosthetic gathering

… .(Protein part)… .(Non-protein part)

CLASSIFICATION OF ENZYME (ON THE BASIS OF FUNCTIONS)

(1) OXIDOREDUCTASE

Catalyze responses in which one substrate is oxidized while other is diminished. Sub classes are:

Dehydrogenases(convert single attach to twofold bond)

Oxidases (use oxygen as oxidant)

Peroxidases (use H202 as oxidant)

Hydroxylases (present hydroxyl aggregate)

Oxygenases (present mol. Oxygen set up of twofold bond).

(2) TRANSFERASES

Exchange one carbon aggregate (e.g. methyl) starting with one substrate then onto the next substrate.

(3) HYDROLASES

Catalyze hydrolytic cleavage of C-O, C-N, C-C and P-O bonds and other single bonds (e.g. Peptidases, Esterases, Glycosidases and Phosphatidases).

(4) LYASES

Catalyze Elimination responses to frame twofold bond and reversible response by including assembles crosswise over twofold bond (e.g. Decarboxlases, Aldolases and Dehydratases).

(5) ISOMERASES

They adjust the structure yet not the nuclear organization by moving a gathering starting with one position then onto the next in one particle (e.g. Epimerases, Mutases).

(6) LIGASES

Catalyze response in which two particles are joined. They are otherwise called synthtases.

Role OF ENZYME

The enzyme react with (energy rich or energy poor) molecules and forms an intermediate complex that breaks into

(a) Product

(b) Enzyme

(i) Substrate + Enzyme = Complex

(ii) Complex = Product + Enzyme

The balance is accomplished if the proportion of conc of reactants (substrate) and item stays same.

Rate of response 1/µ Energy of enactment

Mode OF ACTION OF ENZYMES

1-The activity of protein relies on upon its concoction structure. An ordinary protein particle, has “3D” structure.

2-Has wretchedness or pit for substrate (to fit in) known as “Dynamic site”.

3-Any other site other than dynamic site is called “Allosteric site”

There are two hypotheses in regard of protein activity, which are as per the following.

LOCK AND KEY MODEL

Proposed by Fischer (1898) and altered by Paul Filder and D.D Woods as per this model,

The dynamic site of catalyst has unmistakable shape.

It permits few substrate to fit in (like a specific bolt permits specific key to fit in)

Catalyst breaks substrate to item

INDUCE FIT MODEL

Proposed by koshland (1959), it expresses that

Catalyst ties with a substrate

This coupling incite changes in protein structure

Because of this change catalyst acts and structures item

Calculates AFFECTING ENZYME ACTIVITY

The movement of proteins rely on upon taking after variables,

1. SUBSTRATE CONCENTRATION

Increments with increment in substrate fixation (up as far as possible)

At high fixation, action again diminishes because of immersion of catalyst with substrate and immersion of item i.e. higher grouping of item.

2. TEMPERATURE

Increments with in temperature(up to restricts)

Most extreme action at ideal temperature.

Very dynamic at 37˚C and demolished at 100˚C

At 0˚C least action.

3. PH

Chemicals are pH particular i.e. work in particular pH(because of protein can act both in acidic and essential medium.

4. WATER

Chemical action is normally greatest (up to restricts) yet diminish after points of confinement (weakening of compound)

5. RADIATIONS

Chemicals get to be inert because of radiations (counting Alpha, Beta, Gamma beams).

6. CO-ENZYME AND ACTIVATORS

Actuate the chemical action.

THINGS TO BE REMEMBER

INHIBITORS

Substances which diminishes the action of chemicals.

COMPETITIVE INHIBITORS

Inhibitor atoms which look like the typical substrate particle and vie for entrance into the dynamic site. They hinder the substrate from entering dynamic site.

NON-COMPETITIVE INHIBITORS

Inhibitors tie to a part of the proteins far from the dynamic site (Allosteric site). This coupling cause change in the protein atom shape and decline in chemical movement.

FEED BACK INHIBITION

Normal natural control instrument of mind with a specific end goal to direct catalyst action.

PROSTHETIC GROUP

Non-protein some portion of compound (Co-chemical or Co-variable)

CO-ENZYME

At the point when prosthetic gathering comprise of natural atoms (like FAD/NAD)

CO-FACTORS/ACTIVATORS

At the point when prosthetic gathering comprise of inorganic atoms (like Ca++, Na+ and so forth).

APOENZYME

Protein some portion of catalyst.

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